Minimally invasive cartilage reshaping

June 18, 2019

Molecular surgery makes it possible to reshape cartilage without cutting, suturing, recovery or scars.

If a scientist’s microscopic technique for reshaping living tissue pans out, it could change traditional incisional surgeries to reshape the nose or ears, according to research presented April 2 at a meeting of the American Chemical Society.

Michael Hill, Ph.D., chemistry chair at Occidental College, Los Angeles, is developing a molecular surgery process using tiny needles, electric current and 3D-printed molds to reshape living tissue without incisions, pain, recovery time or potential scarring, according to an American Chemical Society press release.

“We envision this new technique as a low-cost office procedure done under local anesthesia,” says Dr. Hill in the release. “The whole process would take about five minutes.”

A facial reconstructive surgeon Brian Wong, M.D., Ph.D., at the University of California, Irvine, asked Dr. Hill to develop molecular surgery as an option that would noninvasively reshape cartilage for use in cosmetic procedures, including rhinoplasty. Dr. Wong is an expert in a technique that uses infrared laser to heat cartilage in order to make it more flexible and easier to shape. But the heating technique is expensive and it’s difficult to heat the cartilage enough so that it’s moldable without destroying tissue, according to the release.

In an accompanying video, Dr. Hill explains this is not a thermal technique. Rather, it involves passing current through cartilage to electrolyze water in the tissue.

“So, you can get shape change without changing the temperature whatsoever,” Dr. Hill says. “As it turns out, it has to do with water electrolysis. The structure of cartilage is an ionic matrix. There are fixed negative charges and cations that balance that negative charge. The density of those charges holds the cartilage in its conformation and give it structure rigidity.”

The molecular basis of this, as Hill and colleagues discovered, is that when current is passed through cartilage, it oxidizes water, generates oxygen and, more importantly, generates protons, he says.

“They protonate the negative charge and it literally makes the tissue soft and malleable and floppy,” he says.

Dr. Hill demonstrates in the video by folding over his ear.

“…I would take a mold and hold it in this mechanical deformation and insert needles, generate acid and soften the tissue, re-equilibrate the pH and, if I let go of it, my ear would stay bent,” he says. “That’s sort of the basis of the technology.”

Dr. Hill and colleagues tested the method on a rabbit’s ear, which would normally stand up straight. Using a mold, they held one ear in the desired shape and bent position, then inserted microneedle electrodes into the ear at the bend. They pulsed current with the mold in place. The cartilage softened at the bend without damage. Then they turned off the current and the cartilage hardened in the new shape and bend before they removed the mold.

Without the current, the ear would have sprung back upright once the mold was removed, according to the release.

Cartilage is not the only thing made up of this collagen-rich extracellular matrix, so Dr. Hill and colleagues have been studying molecular surgery in different tissue types, including the cornea. They’re exploring licensing options, according to the release.